T EDM P Spin EDM Spin Search for

+ + T + _ _ EDM _ P Spin EDM Spin Search for the Schiff Moment of Radium-225 Zheng-Tian Lu Physics Division, Argonne National Laboratory Department of Physics, University of Chicago

EDM Searches in Three Sectors Quark EDM Nucleons (n, p) Nuclei (Hg, Ra, Rn) Quark Chromo-EDM Electron in paramagnetic molecules (Yb. F, Th. O) Electron EDM Physics beyond the Standard Model: SUSY, etc. Sector Exp Limit (e-cm) Method Standard Model Electron 9 x 10 -29 Th. O in a beam 10 -38 Neutron 3 x 10 -26 UCN in a bottle 10 -31 199 Hg 3 x 10 -29 Hg atoms in a cell 10 -33 M. Ramsey-Musolf (2009)

The Seattle EDM Measurement 199 Hg stable, high Z, groundstate 1 S 0, I = ½, high vapor pressure E Optical Pumping E 7 p 3 P 1 m. F = -1/2 F = 1/2 m. F = +1/2 Courtesy of Michael Romalis s+ 7 s 2 1 S 0 F = 1/2 m = -1/2 F m. F = +1/2

The Seattle EDM Measurement 199 Hg stable, high Z, groundstate 1 S 0, I = ½, high vapor pressure E E Courtesy of Michael Romalis Limits and Sensitivities • Current: < 3 x 10 -29 e-cm -- Griffith et al. , PRL (2009) • Next 5 years: 3 x 10 -30 e-cm • Beyond 2020: 6 x 10 -31 e-cm 15 Hz f

1 S 0

EDM of 225 Ra enhanced and more reliably calculated • Closely spaced parity doublet – Haxton & Henley, PRL (1983) • Large Schiff moment due to octupole deformation – Auerbach, Flambaum & Spevak, PRL (1996) • Relativistic atomic structure (225 Ra / 199 Hg ~ 3) – Dzuba, Flambaum, Ginges, Kozlov, PRA (2002) Parity doublet |a - = |b (|a - |b )/ 2 55 ke. V + = (|a + |b )/ 2 Enhancement Factor: EDM (225 Ra) / EDM (199 Hg) Isoscalar Isovector Skyrme SIII 300 4000 Skyrme Sk. M* 300 2000 Skyrme SLy 4 700 8000 Schiff moment of 225 Ra, Dobaczewski, Engel, PRL (2005) Schiff moment of 199 Hg, Dobaczewski, Engel et al. , PRC (2010) “[Nuclear structure] calculations in Ra are almost certainly more reliable than those in Hg. ” – Engel, Ramsey-Musolf, van Kolck, Prog. Part. Nucl. Phys. (2013) Constraining parameters in a global EDM analysis. – Chupp, Ramsey-Musolf, ar. Xiv 1407. 1064 (2014)

EDM measurement on 225 Ra in a trap 225 Ra: I=½ t 1/2 = 15 d Collaboration of Argonne, Kentucky, Michigan State • Efficient use of the rare 225 Ra atoms • High electric field (> 100 k. V/cm) Oven: 225 Ra • Long coherence time (~ 100 s) • Negligible “v x E” systematic effect Transverse cooling Zeeman Slower Magneto-optical Trap (MOT) Statistical uncertainty 100 d 100 k. V/cm 100 s 106 Long-term goal: dd = 3 x 10% 10 -28 e cm EDM measurement Optical dipole trap (ODT)

Trap Lifetimes Magneto-Optical Trap (MOT) in the first trap chamber Optical Dipole Trap (ODT) in the EDM chamber

Optical Dipole Trap • Fiber laser: l = 1550 nm, Power = 40 Watts • Focused to 100 mm trap depth 400 m. K EDM in an optical dipole trap – Fortson & Romalis (1999) • • • v x E , Berry’s phase effects suppressed Cold scattering suppressed between cold Fermionic atoms Rayleigh scat. rate ~ 10 -1 s-1 ; Raman scat. rate ~ 10 -12 s-1 Vector light shift ~ m. Hz Parity mixing induced shift negligible Conclusion: possible to reach 10 -30 e cm for 199 Hg

Apparatus Argonne National Lab 10

Preparation of Cold Radium Atoms for EDM • 2006 – Atomic transitions identified and studied; N. D. Scielzo et al. , PRA Rapid 73, 010501 (2006) J. R. Guest et al. , PRL 98, 093001 (2007) • 2007 – Magneto-optical trap (MOT) of radium realized; • 2010 – Optical dipole trap (ODT) of radium realized; R. H. Parker et al. , PRC 86, 065503 (2012) • 2011 – Atoms transferred to the measurement trap; • 2012 – Spin precession of Ra-225 in ODT observed; • 2014 – Attempt to measure EDM of Ra-225. MOT & ODT Precession frequency: Sideview Head-on view ODT 0. 04 mm 11

B & E Fields Installed EDM (d) measurement: B = 10 m. G E = 100 k. V/cm

Spin Precession – Oct, 2014 Expected period = 56(6) ms Period = 69(11) ms Period = 70(10) ms

Absorption Detection of Spin State F = 3/2 1 P 1 Photons scattering events 2 -3 photons per atom F = 1/2 Signal-to-noise Ratio For 100 atoms, SNR ~ 0. 2 483 nm 1 S 0 F = 1/2 m. F = -1/2 +1/2 Ra-226 Atom number detection Ra-225 Spin detection

STIRAP (stimulated Raman adiabatic passage) F = 3/2 1 P 1 F = 1/2 1429 nm 483 nm 3 D 1 S 0 1 F = 1/2 m. F = -1/2 +1/2 Stimulated, Adiabatic process No fluorescence

Absorption Detection on a Cycling Transition m. F = +3/2 F = 3/2 1 P 1 Photons scattering events 2 -3 photons per atom 100 -1000 photons per atom F = 1/2 Signal-to-noise Ratio For 100 atoms, SNR ~ 0. 2 For 100 atoms, SNR ~ 10 483 nm 3 D 1 S 0 F = 1/2 m. F = -1/2 +1/2 1

7 p 1 P 6 ns 7 p 1 P 11 6 ns P Puum m p p #1 #1 6 d 1 D 2 430 ms 420 ns 7 p 3 P 11 Slo w& Tr. Ta rpa, p 7 , 1741 n 4 m nm 6 d 3 D 2 7 s 2 1 S 00 6 d 3 D 11 Improve trapping efficiency with a blue upgrade

7 p 1 P 6 ns 7 p 1 P 11 6 ns Pu 3 # mp P Puum m p p #1 #1 #2 Scheme 420 ns 7 p 3 P 11 6 d 3 D 2 Slo w& Tr. Ta rpa, p 7 , 1741 n 4 m nm Slow, 483 nm p m Pu 6 d 1 D 2 430 ms Improve trapping efficiency with a blue upgrade 7 s 2 1 S 00 6 d 3 D 11 KVI barium trap S. De et al. PRA (2009) • 1 st slowing laser: 483 nm (strong) • 2 nd slowing laser: 714 nm • 3 repumpers: 1428 nm, 1488 nm, 2. 75 mm • 171 Yb as co-magnetometer * 225 Ra and 171 Yb trapped, < 50 mm apart Benefits • 100 times more atoms in the trap • Improved control on systematic uncertainties

233 U 225 Ra Yields a 225 Ac a Fr, Rn, … ~4 hr 10 d 229 Th b a 7. 3 kyr 225 Ra 15 d Presently available • National Isotope Development Center, ORNL • Decay daughters of 229 Th 225 Ra: Projected • FRIB (B. Sherrill, MSU) • Beam dump recovery with a 238 U beam • Dedicated running with a 232 Th beam 6 x 109 /s 5 x 1010 /s • • 159 kyr ISOL@FRIB (I. C. Gomes and J. Nolen, Argonne) • Deuterons on thorium target, 1 m. A x 400 Me. V = 400 k. W 1013 /s MSU K 1200 (R. Ronningen and J. Nolen, Argonne) • Deuterons on thorium target, 10 u. A x 400 Me. V = 4 k. W 1011 /s 108 /s 19

Outlook • 2014 -2015 • Implement STIRAP – more efficient way to detect spin; • Longer trap lifetime; • 2015 -2018, blue upgrade – more efficient trap; • Five-year goal (before FRIB): 10 -26 e cm; • 2020 and beyond (at FRIB): 3 x 10 -28 e cm; • Far future: search for EDM in diatomic molecules • Effective E field is enhanced by a factor of 103; • Reach the Standard Model value of 10 -30 e cm.

“Cold” Atom Trappers Argonne: Kevin Bailey, Michael Bishof, John Greene, Roy Holt, Nathan Lemke, Zheng-Tian Lu, Peter Mueller, Tom O’Connor, Richard Parker; Kentucky: Mukut Kalita, Wolfgang Korsch; Michigan State: Jaideep Singh; Northwestern: Matt Dietrich.